Action of Trypsin on Synthetic Substrates

Abstract

The rates of hydrolysis of synthetic substrates by trypsin depend chiefly on the nature of the sensitive amino acid residue. Acylamino acid amides or esters containing L-arginine or L-lysine at the carbonyl moiety of the susceptible bond fulfil optimal structural requirement ; benzoylarginine amide or methyl ester is one of the typical synthetic substrates known for the enzyme (1,2). Although the side chain specificity of the sensitive amino acids forming the susceptible bond is a dominant factor, it should be mentioned that the hydrolytic rate of the susceptible peptide bond in a polypeptide or protein may also be influenced by the size and the spacial configuration of the peptide chain which is combined with the amino group of the sensitive amino acids. In this connection, it seemed desirable to examine the mode and rates of hydrolysis of the peptide amides (glycyl)_n-L-lysinamide by trypsin in which n are 1, 2, 3, and 4. It should be noted that the previous communication from this laboratory dealing with the action of carboxypeptidase on the peptides (glycyl)_n-L-tyrosine in which n are 1, 2, 3, 4, and 5, has revealed that (glycyl)_n-L-tyrosines (n=2∼5) were hydrolyzed approximately 200 times rapidly than glycyl-L-tyrosine (3).